Successful use of esters of transesterified natural oils in combination with high monounsaturation vegetable oils as environmentally friendly, that is biodegradable, base fluids in industrial applications and also as a fuel additive when mixed with normally liquid fuels, is contingent upon improving their low temperature viscometries. For example, a methyl ester obtained from the transesterification of rapeseed oil, has utility as an environmentally friendly diesel fuel. However, this methyl ester has a pour point of -12.degree. C. and solidifies at 13.6.degree. C. which results in clogged filters and engine failure. A sunflower oil containing an oleic acid content of 80 percent has a pour point of -12.degree. C. and also solidifies. Many of the industrial applications require a pour point of less than -25.degree. C. and a Brookfield viscosity of 7500 to 110,000 centiPoises (cP) at -25.degree. C. In order to take advantage of the biodegradability of transesterified esters of natural oils in combination with high monounsaturation vegetable oils it becomes necessary to lower the pour point.
U.S. Pat. No. 2,243,198 (Dietrich, May 27, 1941) relates to non-viscous normally liquid hydrocarbon oils and more particularly to the production of fuel oils having improved flow characteristics under low temperature conditions. The flow characteristics of fuel oil is improved by the addition of a hydrogenated castor oil derivative to a non-viscous normally liquid hydrocarbon oil. Hydrogenated castor oil derivative is defined as the product obtained by reacting hydrogenated castor oil either with its own hydroxyl group or with another organic compound selected from the classes of alcohols, aldehydes, acids, isocyanates and isothiocyanates.
U.S. Pat. No. 3,598,736 (Van der Meij et al, Aug. 10, 1971) relates to soluble polyalkylmethacrylates which can be used in lubricating oil compositions to reduce the pour point. Within the polyalkylmethacrylate the alkyl group has from 10-20 carbon atoms and meets the following three requirements:
(1) The average number of carbon atoms of the alkyl chains in the methacrylates is between 13.8 and 14.8. PA1 (2) The molar percentage of the alkyl methacrylates with branched alkyl chains is between 10 and 30. PA1 (3) The molar percentage of the alkyl methacrylates with an odd number of carbon atoms in the alkyl chain is between 20 and 50. PA1 (b) n=11-22; PA1 (c) a=2.sub.n+1, 2.sub.n-1, 2.sub.n-3, 2.sub.n-5, or 2.sub.n-7 ; and PA1 (A) at least one vegetable or synthetic triglyceride, PA1 (B) esters from the transesterification of at least one animal or vegetable oil triglyceride, PA1 (C) a pour point depressant, and PA1 (D) a performance additive. PA1 (E) other oils. PA1 (1) Aliphatic hydrocarbon groups; that is, alkyl groups such as heptyl, nonyl, undecyl, tridecyl, heptadecyl; alkenyl groups containing a single double bond such as heptenyl, nonenyl, undecenyl, tridecenyl, heptadecenyl, heneicosenyl; alkenyl groups containing 2 or 3 double bonds such as 8,11-heptadecadienyl and 8,11,14-heptadecatrienyl. All isomers of these are included, but straight chain groups are preferred. PA1 (2) Substituted aliphatic hydrocarbon groups; that is groups containing non-hydrocarbon substituents which, in the context of this invention, do not alter the predominantly hydrocarbon character of the group. Those skilled in the art will be aware of suitable substituents; examples are hydroxy, carbalkoxy, (especially lower carbalkoxy) and alkoxy (especially lower alkoxy), the term, "lower" denoting groups containing not more than 7 carbon atoms. PA1 (3) Hetero groups; that is, groups which, while having predominantly aliphatic hydrocarbon character within the context of this invention, contain atoms other than carbon present in a chain or ring otherwise composed of aliphatic carbon atoms. Suitable hetero atoms will be apparent to those skilled in the art and include, for example, oxygen, nitrogen and sulfur.
These polymers are capable not only of considerably depressing the pour point of light lubricating oils, such a spindle oil and light machine oil, but show in addition a high activity as pour point depressants in heavy lubricating oils rich in residual components, such as heavy machine oil.
U.S. Pat. No. 3,702,300 (Coleman, Nov. 7, 1972) relates to a carboxy-containing interpolymer in which some of the carboxy radicals are esterified and the remaining carboxy radicals are neutralized by reaction with a polyamine compound having one primary or secondary amino group and is useful as an additive in lubricating compositions and fuels. The interpolymer is especially effective to impart desirable viscosity characteristics and anti-sludge properties to a lubricating oil.
U.S. Pat. No. 4,284,414 (Bryant, Aug. 18, 1981) relates to the use of mixed alkyl esters made by reacting two or more of certain monohydric alcohols with interpolymers which contain units derived from (i).varies..beta.-unsaturated dicarboxylic acids, or derivatives thereof and (ii) vinyl aromatic monomers having up to 12 carbon atoms in crude oils. Minor amounts of the mixed alkyl esters are useful for modifying the fluidity and flow characteristics of crude oils, and more particularly, for improving the pipeline pumpability of crude oils.
U.S. Pat. No. 4,364,743 (Erner, Dec. 21, 1982) relates to a fuel source for oil burning devices which is a fuel in and of itself or can be mixed with petroleum middle distillates. Fatty acids of the formula ##STR1## can provide such a fuel wherein (a) R is (1) an alkyl radical having from 1 to 12 carbon atoms, (2) alkoxy alkyl wherein the alkoxy portion has from 1 to 4 carbon atoms and the alkyl portion is ethyl or propyl, (3) cyclopentyl or cyclohexyl and (4) hydroxy ethyl and hydroxy propyl;
(d) x is 0 or 1.
U.S. Pat. No. 4,575,382 (Sweeney et al, Mar. 11, 1986) relates to a vegetable oil containing middle distillate fuel characterized by an improved thermal stability. The vegetable oils which may be used include soybean oil, peanut oil and sunflower seed oil.
U.S. Pat. No. 4,695,411 (Stem et al, Sep. 22, 1987) relates to a process for manufacturing a major portion of ethyl esters usable as gas oil substitute motor fuel by transesterification of an animal or vegetable oil optionally containing free acids.
U.S. Pat. No. 4,767,551 (Hunt et al, Aug. 30, 1988) relates to overbased copper-containing lubricant compositions with improved stability and antiwear and antirust properties wherein the overbased copper-containing composition inhibits the oxidation of the lubricant and preserves the antirust properties of the lubricant without significantly decreasing the antiwear properties of the zinc dialkyldithiophosphate antiwear additive during use of the lubricant in an operating engine. Further, this reference provides lubricating oil compositions containing a lubricating oil, a dispersant, a viscosity index improver dispersant, an antiwear agent and a dispersant/detergent, antioxidant and rest inhibitor comprising an overbased copper-containing composition which provides an improved lubricating oil formulation for high speed, high temperature gasoline and diesel engine operation.
U.S. Pat. No. 4,783,274 (Jokinen et al, Nov. 8, 1988) is concerned with an anhydrous oily lubricant, which is based on vegetable oils, which is substituted for mineral lubricant oils, and which, as its main component, contains triglycerides that are esters of saturated and/or unsaturated straight-chained C.sub.10 to C.sub.22 fatty acids and glycerol. The lubricant is characterized in that it contains at least 70 percent by weight of a triglyceride whose iodine number is at least 50 and no more than 125 and whose viscosity index is at least 190. As its basic component, instead of or along with the said triglyceride, the lubricant oil may also contain a polymer prepared by hot-polymerization out of the said triglyceride or out of a corresponding triglyceride. As additives, the lubricant oil may contain solvents, fatty acid derivatives, in particular, their metal salts, organic or inorganic, natural or synthetic polymers, and customary additives for lubricants.
U.S. Pat. No. 5,160,506 (Schur et al, Nov. 3, 1992) relates to a liquid fuel mixture, comprising a C.sub.3 and/or at least a C.sub.4 -alkane, at least one oil component and optionally at least one additive, a process for its preparation and its use for two-stroke engines.